Child killer. Monster. Psychopath. When Robert and Sandra Lane welcomed their first child into the world 40 years ago, a baby girl they called Keli, they could never have dreamed she would grow up to be called these names.

Yet for the past five years, since their first-born was sent to prison for killing her two-day-old daughter Tegan (after a secret pregnancy in 1996, when Keli was only 21), this has been the lot of the Lane family.

They have maintained a steadfast silence.

Until now.

Ever since Keli first appeared on the nightly news back in 2005 as a coronial inquest into Tegan’s disappearance unfurled, Robert and Sandra have been constant but silent players in this fascinating drama.

Yet now, with all avenues of legal appeal against Keli’s sentence exhausted and with the news – revealed exclusively last month in The Weekly – that her case has been taken on by The Bridge of Hope Innocence Initiative at RMIT University, Keli’s parents are speaking out for the first time.

“As far as Sandra and I are concerned, we won’t believe that Tegan is dead until there is a body,” says Robert. “And to date, there has neither been a body produced nor any credible motive. This has been a harrowing experience for our entire family from start to finish.”

Now 70 and 67 years old respectively, Robert and Sandra Lane are still proud members of their all-important community – but their once elevated status has been tarnished. They still occasionally feel the stares and catch the whispered conversations of locals as they walk down the streets of Manly, the northern Sydney suburb in which they live.

“This is something we have been living with for 13 years,” says Robert. “We still live every day under the enormous pressure that this case has brought to bear. And we don’t say that to seek sympathy – it’s just a statement of fact. It’s a daily reality in our lives. Our daughter is in prison for a crime we don’t believe she committed. It’s a heavy burden to carry.”

Keli went to jail in 2010 for the murder of her two-day-old child, Tegan – a little girl she had given birth to alone and in secret, in a Western Sydney hospital 14 years previously.

In a court hearing which compelled the nation, the strange life of this seemingly normal surf-life-saving, water-polo champion from Sydney’s affluent North Shore was laid bare.

Over a period of four years from when she was a teenager, Keli had secretly carried to term and given birth to three children. Without any of her friends or family knowing, she adopted out her first and third child – and says she gave her second child, Tegan, to her biological father, a man with whom she had had a brief affair and whose name she can’t clearly recall.

A 12-person jury was unconvinced and sent her to jail for murder. She was sentenced to 18 years, with a non-parole period of 13 years and five months.

Robert and Sandra say they believe Keli when she says she gave Tegan to her natural father.

“Tegan is with her father,” says Sandra. “And there could be a hundred explanations for why he hasn’t come forward.”

At the height of the trial – and during the coronial inquest five years previously – the Lanes learned first-hand what it was to be caught in the middle of a full-scale media maelstrom. Steadfast in their refusal to speak to the media – either during court proceedings or in any kind of paid-for interview afterwards – they remember being at home one afternoon to discover a reporter had broken into their house.

They won’t be drawn on the question of what it feels like to know they have grandchildren they will probably never meet. Arguably, the drama their daughter has brought into their lives is sufficient without adding any more layers of complication.

Their focus, they say, is on supporting their daughter. “We go out and visit Keli every weekend,” says Sandra. “One of us is out there one week or the other. To give her support and to let her know that we back her 100 per cent.

“As a mother, it’s not an easy thing to see your daughter in prison going through something like this. But she is my child and I love her, and I will stand by her no matter what.”